A flow selector regulates the flow rate of a fluid from a source, e.g., a fluid pump, to a final receiving point, e.g., a patient, through one or more fluid-carrying channels, e.g., polyvinyl chloride (PVC) or silicone-based tubes. In the context of a patient receiving medication, a flow selector allows for adjustment of the dose of medication as deemed appropriate during therapy. Flow selectors have been used in conjunction with fluid pumps that have fixed rates of flow output.